Dust guard



Oct. 19, 1954 Filed July 24, 1952 A. J. LAYBERGER DUST GUARD 3Sheets-Sheet l y j a7 41? INVENTOR. flizwamflnyas/wzfi OCt. 19, 1954LAYBERGER DUST GUARD 1 Filed July 24, 1952 3 Sheets-Sheet 2 [HUME];

fl 3/73 I: I Q U I i l l i I 5 I I ia l I l l i L] A INVENTOR.

O t. 19, 1954 A. J. LAYBERGER DUST GUARD 3 Sheets-Sheet 3 Filed July 24,1952 lNV TOR BY 3 ATTQ NEY Patented Oct. 19, 1954 DUST GUARD Arthur J.Layberger, Havcrtown, Pa., assignor to Pennsylvania Crusher Company,Philadelphia, Pa., a. corporation of New York Application July 24, 1952,Serial No. 300,719

6- Claims.

This invention relates to a dust guard for a reversible type hammermillto intercept the dust carried around by the hammers and forced up thefeed chute.

This application is a continuation in part of my copending applicationSerial Number 178,798, filed on August 11, 1950, entitled Dust Guard,now issued as Patent No. 2,609,996.

The object of the invention is to provide a hammermill type crusher witha feed chute having a dust guard mechanism cooperating with the hammersand casing to intercept and divert dust. created by the crushing processand prevent the dust from escaping out through the feed chute into theatmosphere outside the casmg.

Another object of the invention is to provide a dust guard that iseasily and readily adjust able. from outside the feed chute.

Another object of the invention is to provide a dust guard that isreadily settable at different positions with relation to the rotatinghammers.

Another object of the invention is to provide a dust guard that isinexpensive and durable in construction.

Other and further objects of the invention will appear from thefollowing description taken in connection with the accompanying drawingsof wh ch:

Fig. l is a top view of the dust uard;

Fig, 2 is a cross-sectional view of the dust guard along lines 2-2 ofFig. 1;

Fig. 3 is a cross-sectional view along lines 33 of F s- 1;

Fig. i is a fragmentary end view of another embodiment of: theinvention;

Fig. 5 is a fragmentary side view of the other embodiment of the dustguard;

Fig. 6 illustrates an end view of the Fig. 4; and

Fig. 7 illustrates schematically various positions of the dust guard.

Referring to Figs. 1, 2 and 3 of the drawings there are shown thehammers Ill of a reversible type hammermill crusher mounted on a drivenrotor (not shown) and subscribing a hammercircle H on rotation, On eachside of the rotating hammers are breaker surfaces I3 and [4 againstwhich the material dropped through the feed chute I2 is hit by thehammers. The material is smashed against the breaker surfaces andshattered into smaller particles. The breaker surfaces are arranged onboth sides of the feed chute l2 and are spaced above the hammers I0 toterm a. breaker chamber (6. The breaker surfaces are shown schematicallysince the detail construction and arrangement of these surfaces varieswith the type of material to be crushed and the size of crushed materialdesired, These surfaces are preferably of the same constuction on eachside of the feed chute so that the rotor may be turned in eitherdirection With the same resulting action of the material against thebreaking surfaces. The broken material is carried by the hammers aroundand down to screen bars (not shown) where the broken material is furthercrushed and dropped through the screen bar. However dust formed by thecrushing process tends to remain within the rotor and be carried upwardsand thrown with the air currents into the breaking chamber and up intothe feed chute. This dust and air currents interfere with the incomingmaterial and the dust eventually escapes out of the top of the feedchute into the atmosphere causing an objectionable suspension of finedust.

To prevent this dust and air currents from entering the breaker chamberI6 and feed chute I2, a plate i1 is positioned in. the breaker chamberit between.- the end of the breaker surface l4 adjacent the chute l2 andthe incoming material and extends almost down to the hammer circle I! asillustrated in Fig. 2. As the hammers It! approach the chute on acounterclockwise rotation, the end of the plate or dust guard i'l breaksthe momentum of the dust and deflects the dust and air currents backinto the hammer circle. The incoming material then drops substantiallyfree from these disturbing air currents and dust from the hammers, l

When the rotor is turned clockwise the plate i1 is raised, swung acrossthe feed chute and lowered into position on the other side of the feedchute. Thus the plate H is utilized as a dust guard for both clockwiserotation and counterclockwise rotation.

The plate I! is mounted within the feed chute l2 and is suspended fromthe rocker arms 53, I9. The arms are mounted on the rota-table shafts 2i, 22 and have counterweights 23, 24 to counterbalance the weight of thearms l8, l9 and the plate l'l. The shafts 2|, 22 are journaled in thebeams 36, 38 respectively and outer end members 41, 44 respectively. Thearms l8, 59 are mounted on the stubs of the shafts 2|, 22 extendingthrough the beams 36, 38 into the chute side of the beams and keyed tothe stubs. Drive gears 42, 45 are secured to the respective shafts 2|,22 and rotate the shafts to adjust the position of the plate I? orswitched from side to side. The. gears 42, 45 are connected to the gears48, U by the chains 41, 49 respectively. The gears 48, 50 are keyed tothe shaft and are rotated together by the worm 52 and gear 53. The wormand gear mechanism provides a slow adjustment of the plate i1 and willhold theplate H in any desired position. The worm 52 is mounted on andkeyed to the shaft 54 with a crank socket 55. The outer ends of theshafts 23, 2! are journaled in the members 45, 44 with safety collars43, 43 on the chute side of the members. The collars 43, 43 cooperatewith the hubs of the gears 42, 45 to prevent excessive axial play of theshafts and to hold the plate i! in the longitudinal position.

The feed chute is of a rectangular shape with recesses 38, 39 inopposite lateral sides. The arms l8, [9 are positioned within therecesses respectively. Longitudinal walls are formed by the beams 34, 36and the plates 26, 28 extending below the beams 34, 35 respectively downto the breaker surfaces l3, I4 respectively. The beams 35, 3! are setfurther apart than the plates 26, 28 to allow space for the ends of thearms I8, l 9.

Projecting'inwardly are central portions 3D, 3! on the beams 36, 34respectively and having the chute surface preferably flush with theinner surface of the plates 26, 21. The lateral sides of the chutes areformed by the plates 25, 2'1 extending from the end plates of thecrusher and flaring outwardly at any angle'to form a sloped bottom 25a,22a to the recesses 38, 39 respectively. The extended portions or Wings55, 5'? of the plate I! fit into the recesses 38, 39 and are clear ofthe material in the chute. Pins 58, 59 are mounted in the edge of thewings and fit in slots 30, 5!. The guides 62, 63, 64, 65 are rigidlymounted on the sloped bottoms 25a, 2711., respectively, and are spacedfrom the adjacent longitudinal wall a distance slightly larger than thewidth of the plate IT. The upper edge of the guides is beveled orrounded to provide a gradual narrowing of the space between the guideand the adjacent wall in order to receive the edge of the plate I? andguide it between the guide and the wall. The bottoms 25a, 27a may beflat, then the'corresponding edge of the plate H would be flat and thebeveled edges would correspondingly be horizontal. However, it ispreferable to have the bottom 25a, 27a at an angle to slide off anyentering material catching v in the recess 38, 39.

The plate I1 is a steel'plate having pins 58, '59

mounted in the ends of plate. The pins 58, 59 fit into radial slots 60,6! in the arms l8, l9 respectively. The slot permits the plate to movesubstantially vertically in the guides 62, 63 or 64, 65.

In an operating position the arms l8, l9 are at a slight angle above thehorizontal'and the pins 58, 59 are positioned at the outer ends of theslots Bil, 6! respectively. The'hammer edge of the plate is spacedslightly above the hammers to prevent the hammer tips from impinging onthe edge of the plate. The plate may be shifted from one side of thechute to the other while the ham-- mers are still rotating. It ispreferable to move the plate away from the hammer and then reverse therotation of the rotor. As the plate is lifted, the pins 58, 59 moveoutwardly in the slots 53, 65, Pig. 2. The plate I? will thentiltslightly and move further upon the beveled edges, Fig. 7a, when thepins 58, 59 will stick to the inner end of'slots 63, El and the armspick the plate I! off of the guides 62, 64 and carry it over the guides55a, 51a, Fig.;7b, toengage the beveled edges. Th pla te tilts slightly,Fig. 7c, and as grades 82, 91 it assumes a vertical position and thepins '16, ll move to the outer end of the slots l8, 19, Fig. 7d. Thearms 24, 25 lower the plate and as it is lowered the pins 73, T! move tothe inner end of the slots 18, 19.

On the longitudinal beams 34, 36 are the center projecting portions 3B,3! 'on opposite sides of the feed chute and extend from one recess tothe other. The projecting portions are preferably flush with thelongitudinal side to form a continuous surface along which the plate I!can slide. These projecting portions also prevent material fromaccumulating behind the plate and falling into the recesses 38, 39.

The beams 34, 35, 36, 31 may extend higher or have rectangular wallsections mounted on the upper flanges of the beams 34, 35, 36, 3? toposi tion the lower edge of the upper portion. of the feed chute abovethe are subscribed by the arms l8, 19 as the plate I7 is moved from oneposition to another. Various other feeding structures may be usedWithout interfering with the dust guard. i

The plate I! can be adjusted to different vertical positions withrelation to the hammer circle depending on the circumstances. The platell may be held in position by the worm and gear mechanism or any othersuitable device. As the hammer circle edge of the plate is worn, thewear 7 tioned by stops 59, 13 mounted on the end or lateral walls of thechute. In Fig. 4 the suspension of one end of the plate is shown by thearms til mounted on a shaft 33 and plate tfi'pivotally mounted at theouter end of the arm. A pin ll supporting the plate is fixedly mountedin the end of the plate 65 and rotatably fits into-the crank arm so asthe crank arm is shifted from one position to the other the plate 65remains vertical. The plate 36 extends into the breaker chamber almostto the hammer circle forming a dust guard. The rotation of the crankarms is limited by the stops 69, it upon which the'crank arm rests andsupports the plate in position. The stops are mounted on the end wallsof the delivery chute. The stops may be made adjustable by the stopsfitting through slots in the Wall and fastened to slide bars l4, 75respectively by clamps '33, H. The plates may beshifted from one'side tothe other by means similar to the mechanism shown in Figs. 1 to 3 or anyother suitable mechanism. The stops could be individually loosened andreset at another position.

Various other modifications and changes may be made in the embodimentsshown without departhammers comprising a plate positioned along theinside of the chute and extendable adjacent the periphery of therotating hammers, rotatably mounted crank arms at the ends of said platepivotally supporting said plate at radially spaced pointson said crankarms to readily shift the plate from one side of the delivery chute tothe other side and to suspend the plate in the space,

between the breaker plates and the periphery of the rotating hammers...

2. A dust guard as claimed in claim 1 wherein the sides of the chute atthe ends of the plate have recesses and the crank arms are mounted inthe recesses clear of the material passing through the feed chute.

3. A dust guard as claimed in claim 2 wherein the plate has portionsextending into the recesses.

4. A dust guard as claimed in claim 3 wherein guides are provided insaid recesses extending longitudinally to the wall and spaced therefromto hold the plate along the chute wall.

5. A dust guard as claimed in claim 4 wherein said arms have radialslots and said plate has a pin at each end fitting in said slots so thatthe 6 plate moves vertically when adjacent the hammercircle.

6. A dust guard as claimed in claim 5 wherein the upper ends of saidguides are beveled to permit the extended portions of the plate to tiltthe plate when it is moved from one side of the chute.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,514,111 Wilson July 4, 1950 2,609,996 Layberger Sept. 9,1952

